Select Bond Portfolio
NORTHWESTERN MUTUAL SERIES FUND INC
Fund classification
Classified from what the fund holds · as of 2026 Q2
Select Bond Portfolio is an actively managed U.S. bond fund.
- Asset class
- Bonds
- Region
- United States
- Management
- Actively managed
- Fund type
- Open-end fund
- Credit quality
- Investment grade
- Rate sensitivity
- Intermediate duration
Fund profile
As filed in the prospectus · 2026 Q2
The primary investment objective of the Portfolio is to provide as high a level of total return as is consistent with prudent investment risk.
The fund invests primarily in investment-grade debt securities selected through fundamental analysis for relative value, seeking securities believed undervalued relative to peers of similar credit quality and interest rate sensitivity. The adviser maintains an overall dollar-weighted average effective duration within 10% of the Bloomberg U.S. Aggregate Index and may engage in active trading to capitalize on opportunities or exit positions that have achieved target returns or become overvalued. The fund normally holds at least 80% of assets in debt securities including U.S. government obligations, mortgage-backed securities, corporate bonds, and asset-backed securities, with up to 20% in foreign securities. Because security selection depends on the adviser's relative value assessments, fund performance may diverge from its duration benchmark.
| Share class | Gross | Net |
|---|---|---|
| C000000082 | 0.32% | 0.31% |
Net is what a holder pays after the adviser's contractual waiver; gross is before it. A waiver can expire.
Portfolio turnover 234.00% · as of 2026 Q2
Allocation
Asset groups · long / short shown separately, never netted · 2026 Q2
| Bonds | 56.26% |
| Securitized | 43.93% |
Sector allocation
The same holdings as Allocation above, grouped by market sector instead of asset type · as of 2026 Q2
| Securitized | 43.8% |
| Government | 28.8% |
| Financials | 5.8% |
| Other | 5.7% |
| 11 smaller | 15.9% |
Government, Securitized and Cash are non-corporate buckets; International is foreign holdings we don’t sector-classify, and Other is the residual (held funds, unresolved names).
Latest quarter
What changed since the fund's previous filing
Largest new: UMBS, TBA ×2, United States Treasury ×6
Largest exited: United States Treasury ×5, UMBS, TBA ×3
Return profile
Total return as filed — price change plus distributions reinvested · trailing figures to Apr 2026
May 2026 and Jun 2026 have been filed since the trailing figures were struck, so they are not in the table above or the curve — every figure here shares one cut-off, which is what makes them comparable with other funds.
Debt profile
What this fund holds — value-weighted across its bond and securitized long positions · as of 2026-06-30
Share of the fund's debt by how its coupon behaves — the fact that decides whether a rate move reaches this portfolio at all.
| Fixed rate | 91.8% |
| Floating rate | 8.2% |
Share of the fund's debt value in each maturity band, shortest first.
| <1y | 0.2% |
| 1-3y | 8.9% |
| 3-5y | 17.1% |
| 5-10y | 16.6% |
| 10y+ | 57.2% |
Based on what filers reported; a filer that never reported a flag also reads as none.
Risk profile
Interest-rate and credit-spread sensitivity, both in years · as of 2026Q2
Most of this fund’s sensitivity is to interest rates, with credit spreads carrying about half as much.
Where the loss would come from. The two shocks are the same size, so this is the balance of the fund's two sensitivities rather than a bet on one moving more.
| Interest rates | 74% |
| Credit spreads | 26% |
Filers report the impact of a 0.01% move only, so the total is our own scaling of that one number and overstates the loss on most bonds — read it as approximate, never as precise. The two sensitivities overlap rather than add up: they measure the same positions against different shocks, which is why the durations above are shown side by side and never summed.
Share of the fund's spread duration carried by each credit tier.
| Investment grade | +2.12 yr |
| High yield | +0.01 yr |
Share of duration at each point, shortest first. A positive figure loses value when spreads widen; a negative one offsets — a credit hedge.
| 3 mo | 0.02 yr | 0% |
| 1 yr | 0.58 yr | 10% |
| 5 yr | 1.66 yr | 28% |
| 10 yr | 2.46 yr | 41% |
| 30 yr | 1.30 yr | 22% |
| 3 mo | 0.01 yr | 0% |
| 1 yr | 0.21 yr | 10% |
| 5 yr | 0.71 yr | 34% |
| 10 yr | 0.82 yr | 38% |
| 30 yr | 0.38 yr | 18% |
The two bands measure the same positions against different shocks and do not add — a Treasury carries rate duration and no spread duration, a floating-rate credit the reverse. Rate tenors are also summed across every currency the fund discloses.
Show the numbers
| Tenor | Rate yrs | IG yrs | HY yrs | IG $/bp | HY $/bp |
|---|---|---|---|---|---|
| 3 mo | +0.02 | +0.01 | +0.00 | $1.8k | $14 |
| 1 yr | +0.58 | +0.21 | +0.00 | $60.1k | $242 |
| 5 yr | +1.66 | +0.71 | +0.00 | $204.1k | $746 |
| 10 yr | +2.46 | +0.81 | +0.00 | $233.0k | $1.3k |
| 30 yr | +1.30 | +0.38 | +0.00 | $109.5k | $380 |
Dollar change per 1bp of spread movement, as filed and sign-anchored. A blank cell was not filed; a zero was.
Holdings
By % of NAV · equity positions carry filed share counts · every resolvable issuer links to its company page
| Ticker | Issuer | %NAV | Value | Shares |
|---|---|---|---|---|
| — | UMBS, TBA5.00% · due 2056-07-13 | 1.93% | $55.61M | — |
| — | United States Treasury4.75% · due 2056-02-15 | 1.89% | $54.26M | — |
| — | United States Treasury2.00% · due 2041-11-15 | 1.63% | $46.89M | — |
| — | United States Treasury3.63% · due 2030-03-31 | 1.57% | $45.15M | — |
| — | United States Treasury3.88% · due 2030-04-30 | 1.37% | $39.31M | — |
| — | United States Treasury3.75% · due 2030-06-30 | 1.32% | $37.84M | — |
| — | United States Treasury3.63% · due 2030-12-31 | 1.23% | $35.35M | — |
| — | Government National Mortgage Association2.00% · due 2051-02-20 | 1.21% | $34.87M | — |
| — | United States Treasury3.00% · due 2049-02-15 | 1.15% | $33.01M | — |
| — | United States Treasury1.38% · due 2050-08-15 | 1.02% | $29.24M | — |
Top 10 positions are 14.31% of net assets, top 25 26.75%, across 240 issuers.
See more of this fund's book
More positions with filed share counts, and the quarter-over-quarter change list rather than the largest few — free with an account, no card required.
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